Tanker for shipping liquefied hydrocarbon gas

ABSTRACT

873,653. Carrying liquid cargo. CONDITIONED POWER CO. S.p.A. July 20, 1959 [July 18, 1958], No. 24845/59. Class 113. In a tanker for conveying liquefied gas under atmospheric pressure and low temperature conditions, the thermally insulated cargo tank 1 is freely supported within the inner hull 3 by the supports 7 which have corrugated webs 8 provided with apertures 9. The space 12 between the inner hall 3 and tank 1 has sufficient width to allow easy access for inspection and can be ventilated by forced or natural draught. The inner hull 3, with the outer hull 2, forms a double hull construction and is fluid tight to act as a collecting sump for any cargo which may escape or be spilled.

D. MARCIANO TANKER FOR SHIPPING LIQUEFIED HYDROCARBON GAS April 2, 1963 5 Sheets-Sheet l INVENTOR DOMENICO MARCIA/V0 Filed July 14, 1959 April 2, 1963' D. MARCIANO 3,083,668

TANKER FOR SHIPPING LIQUEF'IED HYDROCARBON GAS Filed July 14, 1959 3 Sheets-Sheet 2 INVENTOR. DOMFENICO MMC/flA/O April 2, 1963 D. MARCIANO 3,083,658

TANKER FOR SHIPPING LIQUEFIED HYDROCARBON GAS Filed July 14, 1959 s SheetsSheet 5 //V VE/V TOR,

Domenica Marciano by a! Attorneys United States Patent D 3,033,668 TANKER FOR swarm; LIQUEF-ED HYDRQ- CARBON GAS V Domenico Marciano, Rome,lt'aly,-assignor to Conditioned Power Co. S.p.A., Rome, Italy, a company of Italy Filed July 14, 1959 Ser.-No,-826,983 Ciaims priority, application Italy July 18, 1958 2 Claims. (Cl. 114-74) The present'invention'relates'to a-tanker provided with particular features -rendering -said "tanker apt to convey, under low temperature and atmospheric pressure conditions, the liquefied'hydrocarbongas.

The features'of the present "invention meet certain requirements havinganessential importance and concerning theparticulartechnicalproblem arising when a tanker of the concerned type, is to be built.

In other words, the inventive features relate particularly to the principles adopted for conveying by a tanker a liquefied gas, under low temperature and atmospheric pressure conditions, as well as the kind and the particular features of the tanks for said liquefied gas and the system found for connecting said tanks to the ships hull, with the principle of leaving always open to inspection the outer surface of the tanks.

As far as the first cited requirement is concerned, it is to be noted that in this connection have been considered the hydrocarbon liquefied gas which are apt to be used as fuels and for industrial uses, such as methane, propane, butane and the like, and the mixtures thereof.

The purpose to be attained is that of conveying the liquefied gas at a temperature equal to, or lower than the boiling point thereof under atmospheric pressure, within so heat insulated tanks, that the evaporation of the liquefied gas due to heat supplied from outside will be minimized.

Each tank, which must be totally fluid tight, in order to avoid the building up of any pressure due to evaporation must be provided with an automatic vent system for the gas, which may be either lost to atmosphere or recovered and utilized, through a re-liquefaction process, to maintain low the temperature of the liquefied gas inside the tank.

This invention will be further disclosed with reference to the attached drawings, in which:

FIG. 1 shows a side elevational view of a ship embodying the inventive principles;

FIG. 2 shows a top plane view of the ship, horizontally cross-sectioned along the hold plane, both the FIGS. 1 and 2, being largely diagrammatical and intended only to show the arrangement of the tanks, according to this invention, within the ships hull;

FIG. 3 shows a main section of the ship, intended to illustrate the arrangement of the tank;

FIG. 4 shows an elevational view of one of the supporting members for the tanks, and

FIG. 5 shows a cross-sectional view of FIG. 4 taken along the line V--V.

With reference to the drawings, FIGS. 1 and 2 show generally a ship built according to the inventive principles and containing a plurality of tanks 1, fore-and-aft aligned. Obviously, the inventive principle does not affect the size of the ship, her capacity, and the number of tanks for the liquefied gas, the determination of said elements depending only upon the study of the design of the ship with respect to her carrying capacity and her required performance.

FIG. 3 more specifically depicts the embodiment and the arrangement of a generic tank within the ships hull. It is to be noted that the holds enclosing the tanks form a double hull structurally connected, by means and systems issuing from the scope of this invention, to the 3,083,668 Patented Apr. 2, 1963 2 outer hull, so'as to furnish-the ship with an integral contribution to her strength, and to create furthermore a possible collection sump in case-of anyleakage'fro'm the tanks, preventing thus the gas from contacting the metal plates and the structures of the outer hull.

In FIG. 3, the numeral reference 2 denotes 'the outer hull, 3 is the double bill] forming the fluid-tight hold and -4 -is the wall of the tank 1 =-th'e outside surface of which is insulated as shown at "5 by a suitable heat insulating material having the proper thickness.

The tanks are made of a material apt to keep good strength and ductility features also at the low exercise temperatures; said tanks are internally reinforcedas diagrammatically shown at 6 and are built preferably by welding techniques.

Eachtank 1, as clearly's'hown in FIG. 3, isindependent from the ships structure consisting of the outer hull 2, and of the inner double hull Seven if-said tank is :permanently located within the hold.

Each hold, consisting of the doublehullfi, isalsototally fluid tight and a aforesaid it is structurally connected to the outer hull, thus integrally contributing to the ships strength.

The connection between each tank 1, Le. between the outer wall 4 of said tank and the associated hold 3 is embodied by means of support members 7 having the shape of double tee beams, of a flexible type as best shown in FIGS. 4 and 5. Each support 7 consists of a corrugated central web 8 provided with the apertures 9 as shown in FIG. 5. To the ends of the web 8 are fixed the cross flanges 10 and 11.

Considering again the FIG. 3, it has been there shown how the double tee elements are applied between the top 3' of the double bottom (forming the bottom of the hold) and the bottom of the tank, and between the sides of the tank and the side walls of said hold.

The members 7 support the weight of the tank 1, allowing its expansion and contraction due to the possible changes of temperature of the liquefied gas contained within the tank, and because of the fact that they are flexible and have the corrugations in the webs thereof are resiliently compressible and expansible so that they oppose the movements due to the dynamic action of the wavy motion due to their arrangement practically sur rounding the tanks.

The supports 7 undergo slight bending and torsion movements. The supports are fastened to both the walls 3 and the bottom 3 of the hold (double hull) and the outer surface of the insulation is slidable on said supports. It is preferred to provide a separate section of insulation 5' between each support and the tank wall 4, the insulator 5' being more resistant to wear than the insulation 5 used to cover most of the tank.

The metal plates of the holds are made of special steel apt to render said holds suitable to contain the liquefied gas, in case of breaking down or leak of any tank.

The space 12 (FIG. 3) existing between each container and the associated hold has such a width to allow the easy, continuous and complete inspection of both the 1ringer surface of the tank and the inner surface of the This space 12 is provided with an adequate air exchange which can also be obtained as a forced draught by a suitable mechanical ventilation unit (not shown in the figures) in order to diminish the temperature and the hunliidity degree of the ambient space surrounding the tan While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from said principles.

I claim:

1. A ship structure for transporting liquefied petroleum gas, comprising in combination an outer hull, an inner hull mounted in spaced relationship Within said outer hull and defining within said outer hull a gas tight enclosure, support members fixed at spaced points on the bottom and side walls of said inner hull, and projecting into said inner hull, said support members being compressible and expansible in a direction substantially perpendicular to said inner hull, a liquefied petroleum gas tank freely slidably mounted in heat insulating relationship on said supports, a heat insulating layer covering the outer surfaces of said tank, a hard heat insulating layer covering said tank at point contacting said supports, said tank being spaced from the inner hull around the entire periphery of the tank, and slidable on said supports to permit adjustment of the position of the tank relative to the inner hull, the space between the inner hull and the tank being easily accessible for inspecting said heating insulating layer.

2. A ship structure as claimed in claim 1 in which said support comprises beams which are substantially I-shaped in cross section with a web extending between two flanges, said web having a plurality of apertures therein and the portions of said web remaining between said apertures being'corrugated with the corrugations extending parallel to said flanges, the lower flange being rigidly fixed to the inner wall of said inner hull, and the upper flange being freely slidably held against said tank.

References Cited in the file of this patent 'UNITED STATES PATENTS 956,810 Lamasney et al May 3, 1910 1,779,786 Unzue Oct. 28, 1930 2,464,356 Stearns Mar. 15, 1949 2,520,883 Kornemann et al Aug. 29, 1950 2,563,118 Jackson Aug. 7, 1951 2,896,416 Henry July 28, 1959 2,897,657 Rupp Aug. 4, 1959 2,920,850 Campbell Jan. 12, 1960 2,963,873 Stowers Dec. 13, 1960 2,970,559 Leroux Feb. 7, 1961 2,992,622 Maker July 18, 1961 2,993,460 Dreyer July 25, 1961 FOREIGN PATENTS 91,767 Norway May 27, 1958 746,567 Germany Aug. 12, 1944 

1. A SHIP STRUCTURE FOR TRANSPORTING LIQUIFIED PETROLEUM GAS, COMPRISING IN COMBINATION AN OUTER HULL, AN INNER HULL MOUNTED IN SPACED RELATIONSHIP WITHIN SAID OUTER HULL AND DEFINING WITHIN SAID OUTER HULL A GAS TIGHT ENCLOSURE, SUPPORT MEMBERS FIXED AT SPACED POINTS ON THE BOTTOM AND SIDE WALLS OF SAID INNER HULL, AND PROJECTING INTO SAID INNER HULL, SAID SUPPORT MEMBERS BEING COMPRESSIBLE AND EXPANSIBLE IN A DIRECTION SUBSTANTIALLY PERPENDICULAR TO SAID INNER HULL, A LIQUIFIED PETROLEUM GAS TANK FREELY SLIDABLY MOUNTED IN HEAT INSULATING RELATIONSHIP ON SAID SUPPORTS, A HEAT INSULATING LAYER COVERING THE OUTER SURFACES OF SAID TANK, A HARD HEAT INSULATING LAYER COVERING SAID TANK AT POINT CONTACTING SAID SUPPORTS, SAID TANK BEING SPACED FROM THE INNER HULL AROUND THE ENTIRE PERIPHERY OF THE TANK, AND SLIDABLE ON SAID SUPPORTS TO PERMIT ADJUSTMENT OF THE POSITION OF THE TANK RELATIVE TO THE INNER HULL THE SPACE BETWEEN THE INNER HULL AND THE TANK BEING EASILY ACCESSIBLE FOR INSPECTING SAID HEATING INSULATING LAYER. 